In the bulk handling of materials, and especially fluid or flowable materials such as liquids, powders and granules, containers of 20 to 80 gallon capacity are commonly used to transport and store the material. These containers should be capable of withstanding the weight of the contents and of being stacked on top of one another. They should also be capable of withstanding the rough handling to which they may be subjected, and be capable of being handled with mechanized equipment.
A variety of containers have been developed in the prior art in an effort to meet these criteria, including drums made of metal or fibre, plywood bins, and corrugated paperboard containers. While plywood bins and drums made out of metal or fibre possess the requisite strength and durability, they are expensive to manufacture, store and ship.
Corrugated paperboard containers are less costly to make and generally can be collapsed for compact storage and shipment. However, when filled with a fluid product the sidewalk of the container may bulge outwardly, and depending upon the size of the container and weight of the material used in its construction it may be difficult to set up. Further, a flexible bag liner is commonly used when a fluid material is to be contained, and unless special consideration is given to how the container is constructed, the liner may be damaged by elements of the container protruding into the interior of the container.
Bulk containers may be palletized for ease and convenience of handling, and it is desirable that the container or containers efficiently fit the pallet, i.e. that they do not overhang the edges of the pallet, or the edges of the pallet do not extend an excessive distance beyond the perimeter of the container or containers supported thereon. Pallets typically utilized are 40×48 or 44×44 or 44×54 inches in size and are square or rectangular in shape. Cylindrical drums do not efficiently fit a pallet because the circular footprint of the drum leaves void spaces between adjacent drums and at the corners of the pallet. Conventionally constructed square or rectangular containers of corrugated paperboard can be sized to fit a pallet, but if the sidewalls bulge outwardly they can extend beyond the perimeter of the pallet and be subject to damage.
Conventional corrugated paperboard containers strong enough to hold fluid material are either difficult to set up from a flattened condition and/or are too hard to manufacture and/or are too expensive for the end-user. Bulging sidewalls and difficulty in setting them up from a knocked down or flattened condition are the major problems with conventional designs.
There is need, therefore, for a bulk container made of corrugated paperboard that can take the place of a 20 to 80 gallon fibre drum or metal barrel, which can ship flat and be easily opened up for filling, and once it is empty, knocked down flat again for either re-use or recycling. Further, it would be desirable to have a container that can fit four on a pallet, that is reinforced against bulging of the sidewalls, and that maintains proper containment thereby eliminating potential contamination.